Sensor element and sensor array

Abstract

To provide a sensor element capable of suppressing deterioration of sensor characteristics.SOLUTION: A sensor element 100 provided herein comprises a first electrode 16, a second electrode 18, a channel layer 14 made of an atomic layered material, disposed between the first electrode 16 and the second electrode 18, and electrically connected to the first electrode 16 and the second electrode 18, and an insulating layer 20 covering at least edges of the channel layer 14 in a direction perpendicular to an arrangement direction of the first electrode 16 and the second electrode 18.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor element and a sensor array. [Background technology]

[0002] BACKGROUND ART Field effect transistors (FETs) having an atomic layer-like channel layer such as graphene are known as sensor elements used in biosensors and the like.

[0003] In a sensor element, when a target substance is captured by a capture body bonded to the channel, the potential of the channel layer changes. Therefore, the target substance can be detected based on the current flowing through the channel layer. For a sensor element using graphene as a channel layer, it is known to provide an insulating layer on a part of the channel layer and on the electrode, and to provide an opening in the insulating layer through which the end of the channel is exposed (for example, Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the end of the channel layer is exposed through the opening, drift in characteristics may occur, which may affect the sensor characteristics.

[0005] An object of the present invention is to provide a sensor element and a sensor array that suppress deterioration of sensor characteristics. [Means for solving the problem]

[0006] According to an embodiment of the present invention, a sensor element includes a first electrode, a second electrode, a channel layer having an atomic layered material, disposed between the first electrode and the second electrode, and electrically connected to the first electrode and the second electrode, and an insulating layer covering an end of the channel layer at least in a direction perpendicular to an arrangement direction of the first electrode and the second electrode. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sensor element and a sensor array that suppress deterioration of sensor characteristics. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1(a) is a plan view showing a sensor element according to a first embodiment of the present invention, and FIG. 1(b) and FIG. 1(c) are cross-sectional views taken along lines AA and BB of FIG. 1(a), respectively. [Figure 2] FIG. 2 is a cross-sectional view of the sensor element according to the first embodiment of the present invention. [Figure 3] FIG. 3(a) is a plan view of a sensor element according to a first comparative example, and FIG. 3(b) is a cross-sectional view taken along the line AA in FIG. 3(a). [Figure 4] 4(a) and 4(b) are planar schematic views showing the end of the channel layer in the first comparative example, and FIG. 4(c) is a planar schematic view showing the end of the channel layer in the first embodiment of the present invention. [Figure 5] FIG. 5(a) is a plan view of a sensor element according to the first embodiment of the present invention, and FIG. 5(b) is a plan view of a sensor element according to a first modification of the first embodiment of the present invention. [Figure 6] FIG. 6(a) is a plan view of a sensor element according to a second modification of the first embodiment of the present invention, and FIG. 6(b) is a plan view of a sensor element according to a third modification of the first embodiment of the present invention. [Figure 7] FIG. 7(a) is a plan view of a sensor element according to a fourth modification of the first embodiment of the present invention, and FIG. 7(b) is a plan view of a sensor element according to a fifth modification of the first embodiment of the present invention. [Figure 8] FIG. 8(a) is a plan view of a sensor element according to a sixth modification of the first embodiment of the present invention, and FIG. 8(b) is a cross-sectional view taken along the line AA of FIG. 8(a). [Figure 9] FIG. 9 is a cross-sectional view of a sensor element according to a seventh modification of the first embodiment of the present invention. [Figure 10] FIG. 10 is a block diagram of a sensor system in which the first embodiment of the present invention and its modified example are used. [Figure 11]FIG. 11(a) is a plan view showing a sensor element according to a second embodiment of the present invention, and FIG. 1(b) is a cross-sectional view taken along the line AA of FIG. 11(a). [Figure 12] FIG. 12 is a cross-sectional view of a sensor element according to a second embodiment of the present invention. [Figure 13] 13(a) and 13(b) are cross-sectional views of a sensor element according to a second embodiment of the present invention. [Figure 14] FIG. 14(a) is a cross-sectional view of a sensor element according to Modification 1 of the second embodiment of the present invention, and FIG. 14(b) is a cross-sectional view of a sensor element according to Modification 2 of the second embodiment of the present invention. [Figure 15] FIG. 15(a) is a cross-sectional view of a sensor element according to a third modification of the second embodiment of the present invention, and FIG. 15(b) is a cross-sectional view of a sensor element according to a fourth modification of the second embodiment of the present invention. [Figure 16] FIG. 16(a) is a cross-sectional view of a sensor element according to a fifth modification of the second embodiment of the present invention, and FIG. 16(b) is a cross-sectional view of a sensor element according to a sixth modification of the second embodiment of the present invention. [Figure 17] 17(a) to 17(c) are plan views of a sensor element according to a seventh modification of the second embodiment of the present invention. [Figure 18] 18(a) and 18(b) are plan views of a sensor element according to Modification 8 of the second embodiment of the present invention. [Figure 19] 19(a) and 19(b) are plan views of a sensor element according to a ninth modification of the second embodiment of the present invention. [Figure 20] 20(a) to 20(c) are plan views of a sensor array according to a tenth modification of the second embodiment of the present invention. [Figure 21] FIG. 21 is a plan view of a sensor array according to an eleventh modification of the second embodiment of the present invention. [Figure 22] FIG. 22 is a plan view of a sensor array according to a twelfth modification of the second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are examples for embodying the technical ideas of the invention, and the present invention is not limited to the described configurations and numerical values. In each drawing, the same components are given the same reference numerals, and duplicated explanations may be omitted as appropriate. The size, positional relationship, etc. of each component shown in each drawing may be exaggerated to facilitate understanding of the invention.

[0010] (First embodiment) Fig. 1(a) is a plan view showing a sensor element according to a first embodiment of the present invention, and Fig. 1(b) and Fig. 1(c) are cross-sectional views taken along lines AA and BB of Fig. 1(a), respectively. The thickness direction of the substrate 10 is defined as the Z direction, the arrangement direction of the electrodes 16 and 18 as the X direction, and the direction intersecting the X and Z directions as the Y direction.

[0011] As shown in FIGS. 1(a) to 1(c), the sensor element 100 according to the first embodiment includes a substrate 10, insulating layers 12 and 20, a channel layer 14, and electrodes 16 and 18.

[0012] The insulating layer 12 is provided on the substrate 10. If the substrate 10 is an insulating substrate, the insulating layer 12 may not be provided. The channel layer 14 is provided on the insulating layer 12 and includes an atomic layer material. Electrodes 16 and 18 are provided on the substrate 10 and electrically connected to the channel layer 14. The electrodes 16 and 18 are provided to sandwich the channel layer 14 in the X direction. The electrodes 16 and 18 correspond to a source electrode and a drain electrode, respectively.

[0013] The insulating layer 20 is provided on the insulating layer 12 so as to cover the electrodes 16, 18 and the channel layer 14. The insulating layer 20 has an opening 22 that exposes the upper surface of the channel layer 14. The insulating layer 20 functions as a protective film for the electrodes 16 and 18. The insulating layer 20 has openings 17 and 19 that expose the upper surfaces of the electrodes 16 and 18. The openings 17 and 19 function as pads for electrically connecting the electrodes 16 and 18 to the outside.

[0014] The planar shape of the opening 22 is rectangular, for example. The planar shape of the opening 22 can be set as appropriate, such as polygonal or circular. The width of the channel layer 14 in the X direction between the electrodes 16 and 18 is X1, and the width of the channel layer 14 in the Y direction is Y1. The widths of the opening 22 in the X and Y directions are X2 and Y2, respectively. Width X2 is smaller than X1, and width Y2 is smaller than Y1. End E1 of the channel layer 14 is not exposed from the opening 22, and end E1 of the opening 22 is entirely located on the channel layer 14.

[0015] The planar shape of the channel layer 14 is, for example, rectangular. The planar shape of the channel layer 14 can be set appropriately to a polygonal or circular shape, etc. Widths X1 and Y1 are, for example, 1 μm or more and 50 mm or less. Widths X1 and Y1 can be set appropriately.

[0016] Fig. 2 is a cross-sectional view of the sensor element according to the first embodiment of the present invention. Fig. 2 shows the sensor element 100A according to the first embodiment in use. As shown in Fig. 2, the sensor element 100A includes a capture body 25, a sample 30, a pool 36, and a gate electrode 38 in addition to the components shown in Figs. 1(a) to 1(c).

[0017] The capture body 25 is a probe molecule and is bonded to the surface of the channel layer 14 exposed from the opening 22. The capture body 25 forms a receptor layer 28. The sample 30 is a liquid and is held by a pool 36. The sample 30 contains a target substance 32 and a substance 34 other than the target substance 32. The gate electrode 38 is inserted into the sample 30.

[0018] By applying a voltage to the gate electrode 38, an electric double layer is formed near the surfaces of the channel layer 14 and the gate electrode 38, and carriers such as electrons can be induced in the channel layer 14. In this state, when a voltage Vds is applied between the electrodes 16 and 18, carriers such as electrons flow from the electrode 16 to the electrode 18 via the channel layer 14. When the target substance 32 is captured by the capture bodies 25, the potential (Fermi level) of the channel layer 14 changes, and the current (drain current Ids) flowing between the electrodes 16 and 18 changes. The current changes depending on the number of capture bodies 25 that have captured the target substance 32. The concentration of the target substance 32 can be detected by measuring the current value.

[0019] For example, when the channel layer 14 is made of graphene, the voltage Vgs is swept to measure the current Ids. The voltage Vgs at which the current Ids is minimum is the voltage VDirac at the Dirac point, and the concentration of the target substance 32 in the sample 30 can be detected based on the value of the voltage VDirac.

[0020] The substrate 10 may be, for example, a semiconductor substrate such as a silicon (Si) substrate, gallium arsenide (GaAs), or indium phosphide (InP), an insulating substrate such as glass, or a conductive substrate such as a metal substrate. The substrate 10 may also be a flexible resin substrate such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, or silicone rubber (PDMS, polydimethylsiloxane). When a flexible substrate is used as the substrate 10, the sensor element 100 can be placed on a curved surface. For example, the sensor element 100 can be attached to the human body. In this form, the sensor element 100 can be placed in close contact with the body. The sensor element 100 may be capable of sensing gases such as body odor and bodily fluids such as sweat and tears in real time.

[0021] There are no particular limitations on the insulating layers 12 and 20 as long as they are insulating films. The insulating layers 12 and 20 are inorganic insulators such as silicon dioxide (SiO2), aluminum oxide (Al2O3), silicon nitride (SiN), hafnium oxide (HfO2), titanium oxide (TiO2), or tantalum oxide (Ta2O5). The insulating layer 12 may be an organic insulator such as spin-on-glass (SOG) or a fluorine-based resin. The insulating layer 12 may also be a laminate film of the above layers.

[0022] The insulating layer 20 covers the electrode 16 or 18, thereby suppressing leakage current between the electrode 16 or 18 and the gate electrode 38. In order to prevent the channel layer 14 from being affected when the target substance 32 or other substances 34 are adsorbed onto the insulating layer 20, the thickness of the insulating layer 20 is preferably greater than the thickness (i.e., the Debye length) of the electric double layer formed by the sample 30 on the channel layer 14. From these viewpoints, the thickness of the insulating layer 20 is preferably 10 nm or more.

[0023] When the insulating layers 12 and 20 are made of an inorganic insulator, they are formed by, for example, a chemical vapor deposition (CVD) method, a physical vapor deposition (PVD) method such as a sputtering method or an evaporation method, or an atomic layer deposition (ALD) method. When the insulating layers 12 and 20 are made of an organic insulator, they are formed by, for example, a spin coating method, a screen printing method, an offset printing method, a ravia printing method, or an inkjet method.

[0024] The atomic layer material of the channel layer 14 is a two-dimensional material such as graphene or a transition metal dichalcogenide (TMDC) such as molybdenum disulfide (MoS), a one-dimensional material such as a carbon nanotube (CNT) or a silicon nanowire, or a material in which one-dimensional materials are connected in a network form.

[0025] In atomic layered materials, the current changes sensitively with changes in the surface state (surface potential state). Therefore, by using an atomic layered material for the channel layer 14, the detection sensitivity of the target substance 32 can be improved. The channel layer 14 has one or more atomic layers. As the number of atomic layers increases, the sensitivity decreases. From this perspective, the number of atomic layers in the channel layer 14, including a turbostratic structure, is preferably 10 or less.

[0026] The carrier mobility of graphene at room temperature is 200,000 cm 2 / Vs, which is very high. Therefore, by using graphene as the atomic layer material, the detection sensitivity of the sensor element 100 can be increased.

[0027] The electrodes 16 and 18 are made of, for example, palladium (Pd), platinum (Pt), silver (Ag), gold (Au), nickel (Ni), titanium (Ti), chromium (Cr), or aluminum (Al), or a laminate film of these. Palladium and platinum have low contact resistance with graphene, while titanium and chromium have good adhesion with the insulating layers 12 and 20.

[0028] The capture body 25 is a substance that specifically binds to or adsorbs to a target substance 32 in a sample 30, but does not easily bind to or adsorb to other substances 34. The material of the capture body 25 is appropriately selected depending on the target substance 32. For example, if the target substance 32 is a molecule, the capture body 25 is a molecular template corresponding to the target substance 32. If the target substance 32 is an ion, the capture body 25 is an ionophore corresponding to the target substance 32.

[0029] When the target substance 32 is an antigen such as a hormone, the capture body 25 is an antibody corresponding to the target substance 32. When the target substance 32 is a nucleic acid molecule such as DNA (Deoxyribonucleic Acid) or (RNA: Ribonucleic Acid), the capture body 25 is a nucleic acid aptamer such as DNA or RNA corresponding to the target substance 32. When the target substance 32 is an amino acid, a protein, or the like, the capture body 25 is a peptide aptamer corresponding to the target substance 32, or the like.

[0030] When sensing in a liquid, the sample 30 is not particularly limited as long as it is a liquid that can form an electric double layer. To ensure the stability of the characteristics of the sensor element 100, the sample 30 preferably contains a solution such as phosphate buffered saline (PBS) that can maintain a constant pH. Alternatively, the sample 30 may be a body fluid such as saliva, sweat, tears, urine, blood, or plasma.

[0031] For example, when the sensor element 100A senses hormone balance from saliva, blood, urine, tears, or sweat, the target substance 32 may be estrone, estradiol, estriol, progesterone, testosterone, DHT (dihydrotestosterone), androstenedione, androsterone, cortisol (hydrocortisone), serotonin, dopamine, oxytocin, adrenaline, noradrenaline, melatonin, or erythropoietin. By sensing these hormones, the sensor element 100A can visualize stress, happiness, and the like.

[0032] There are no particular limitations on the pool 36 as long as it can keep the sample 30 on the channel layer 14. The pool 36 does not have to be provided as long as it can keep the sample 30 on the channel layer 14. The pool 36 is, for example, an insulating material such as rubber containing polydimethylsiloxane (PDMS) or a thick-film resist.

[0033] The gate electrode 38 may be made of any material as long as it can be electrically connected to the channel layer 14 via the sample 30. The gate electrode 38 may be made of the same material as the electrodes 16 and 18. The gate electrode 38 is preferably made of a silver-silver chloride electrode (Ag / AgCl), a calomel electrode, a palladium-hydrogen electrode (Pd / H2), or the like. This improves the stability and reproducibility of the electrode potential.

[0034] (First Comparative Example) Fig. 3(a) is a plan view of a sensor element according to a first comparative example, and Fig. 3(b) is a cross-sectional view taken along line AA of Fig. 3(a). As shown in Figs. 3(a) and 3(b), a sensor element 130 according to the first comparative example has one opening 22 provided on the channel layer 14. The width Y2 of the opening 22 in the Y direction is larger than the width Y1 of the channel layer 14 in the Y direction. This exposes an end E1 of the channel layer 14 from the opening 22. The other configurations are the same as those of the first embodiment.

[0035] 4(a) and 4(b) are planar schematic diagrams showing the edge of the channel layer in the first comparative example, and FIG. 4(c) is a planar schematic diagram showing the edge of the channel layer in the first embodiment of the present invention. Graphene is shown as an example of the channel layer 14.

[0036] As shown in FIGS. 4(a) and 4(b), the graphene of the channel layer 14 has a structure in which six-membered carbon rings are connected in a plane. In FIG. 4(a), the edge E1 is a zigzag edge 53. In FIG. 4(b), the edge E1 is an armchair edge 54. The edge E1 of the graphene can be a zigzag edge, an armchair edge, or a mixture of these. Localized bonds or the like are formed at these edges E1. The state of the edge E1 can vary depending on the individual sensor element 100.

[0037] In this way, the target substance 32 and other substances 34 may be adsorbed or bound to the localized bonds at the edge E1. For example, the capture body 25 is bonded to the graphene by a π-π stacking bond, but at the edge E1, the capture body 25, the target substance 32, and other substances 34 may unexpectedly bond to each other by bonds other than a π-π stacking bond.

[0038] For example, binding of other material 34 to edge E1 can change the Fermi level of channel layer 14, changing the current Ids flowing between electrodes 16 and 18. This can result in, for example, a drift in voltage VDirac.

[0039] The drift phenomenon is described, for example, in Proceedings of the 66th Spring Meeting of the Japan Society of Applied Physics, Vol. 10a-W521-3. Current drift is a phenomenon in which the current Ids-voltage Vgs characteristic changes over time when the current Ids is measured at a constant gate voltage in a sample 30 that does not contain a capture body 25 and a target substance 32. The fact that the state of the edge E1 differs from the surface state is not a phenomenon unique to graphene, but is thought to occur in atomically layered materials. Therefore, the drift phenomenon can occur in atomically layered materials not only when the channel layer 14 is made of graphene, but also when the channel layer 14 is made of, for example, a transition metal dichalcogenide.

[0040] Furthermore, if the state of the end E1 differs depending on the individual sensor elements 100, the characteristics of the sensor elements 100 will differ depending on the individual sensor elements 100. Furthermore, there is a possibility that the drift phenomenon will occur differently depending on the individual sensor elements 100. In this way, the characteristics of the sensor elements 100 will deteriorate.

[0041] As shown in FIG. 4(c), in the sensor element 100 of the first embodiment, the insulating layer 20 covers the end E1 of the channel layer 14 at least in the Y direction (the direction perpendicular to the arrangement direction of the electrodes 16, 16). This prevents the capture body 25, the target substance 32, and other substances 34 from being adsorbed or bonded to the end E1. This prevents the drift phenomenon caused by the end E1. Furthermore, even if the state of the end E1 differs between individual sensor elements 100, the characteristics of each sensor element 100 can be made uniform. In this way, deterioration of the characteristics of the sensor element 100 can be prevented.

[0042] Furthermore, the channel layer 14 has an exposed region corresponding to the opening 22 that is not covered by the insulating layer 20. This allows the channel layer 14 to capture the target substance 32 in the exposed region.

[0043] When the channel layer 14 directly captures the target substance 32, it is not necessary to provide the capture body 25. By providing the capture body 25 that binds to the atomic layer material, it is possible to capture only the target substance 32 without capturing substances 34 other than the target substance, thereby improving the selectivity of the substance to be captured.

[0044] When the channel layer 14 is made of graphene, the carbon-carbon bond distance is 0.14 nm. If the overlap width ΔY between the channel layer 14 and the insulating layer 20 in the Y direction is greater than 0.14 nm, the end E1 can be covered by the insulating layer 20.

[0045] The actual position of the end E1 in the Y direction is not constant depending on the position in the X direction due to manufacturing errors, etc. Also, there is a problem with the alignment accuracy between the channel layer 14 and the opening 22. From the above perspectives, ΔY is preferably 0.1 μm or more, and more preferably 1 μm or more. As ΔY increases, the ratio of the width Y2 over which the capture body 25 is provided to the width Y1 of the channel layer 14 decreases. This reduces the detection sensitivity of the target substance 32. From this perspective, ΔY is preferably 10 μm or less.

[0046] It is preferable that opening 22 is large enough to allow attachment of capture body 25. If opening 22 overlaps with electrodes 16 and 18, the function of protecting electrodes 16 and 18 will be impaired. Therefore, it is preferable that opening 22 does not overlap with electrodes 16 and 18.

[0047] From the viewpoint of improving the detection sensitivity of the sensor element, it is preferable that the area of ​​the channel layer 14 exposed from the opening 22 is large. In order to enlarge the opening 22, as shown in FIG. 1(a), the planar shapes of the channel layer 14 and the opening 22 are rectangular, and it is preferable that two opposing sides of the four sides of the opening 22 are parallel to two sides of the rectangle of the channel layer 14, and the other two sides of the opening 22 are parallel to the electrodes 16 and 18. Here, the term "rectangle" is not limited to a geometric rectangle and allows for a manufacturing error. Furthermore, the term "parallel" is not limited to a geometric parallel and allows for a manufacturing error. For example, the angle between the two sides may be 10° or less.

[0048] As described above, at least one side of opening 22 is preferably parallel to the side of channel layer 14 connecting electrodes 16 and 18. To enlarge opening 22, width Y2 is preferably 0.5 times or more, more preferably 0.8 times or more, the width Y1. Width X2 is preferably 0.5 times or more, more preferably 0.8 times or more, the width X1.

[0049] (Modification 1 of the first embodiment) FIG. 5(a) is a plan view of a sensor element according to a first embodiment of the present invention. As shown in FIG. 5(a), an object 56 in the sample 30 may adhere to or become caught on a corner 55 of the opening 22. The object 56 may be an object originally contained in the sample 30. The object 56 may also be a precipitate that precipitates when ions are supplied into the sample 30 from the gate electrode 38. The size of the precipitate may be several μm. If the object 56 adheres to or becomes caught on the corner 55 of the opening 22, it may cause a drift phenomenon. It may also affect the conduction characteristics of carriers in the channel layer 14.

[0050] If stress is concentrated at the corner 55 of the opening 22, cracks 57 or the like may occur in the insulating layer 20 at the corner 55 of the opening 22. This affects the conduction characteristics of carriers in the channel layer 14.

[0051] 5(b) is a plan view of a sensor element according to Modification 1 of the first embodiment of the present invention. As shown in FIG. 5(b), in the sensor element 101 according to Modification 1 of the first embodiment, the corners 55 of the openings 22 are curved. That is, in a top view, at least a part of the outline of the exposed region is curved. Note that the top view is from the Z direction (the thickness direction of the channel layer 14). The curve of the corners 55 of the openings 22 is, for example, part of a circle 58, and is smoothly connected at the intersections of the curve and the straight lines of the sides, forming a so-called R-shape.

[0052] This prevents objects 56 from being attracted to or caught on corners 55 of opening 22. It also prevents stress from concentrating on corners 55 of opening 22, causing cracks 57 and the like to form in insulating layer 20. This prevents degradation of characteristics such as drift and conduction characteristics.

[0053] For example, if the gate electrode 38 contains silver and the sample 30 is phosphate buffered saline, the size of the precipitated object 56 is approximately 2 μm. Therefore, the radius of curvature R of the curve is preferably 1 μm or more, and more preferably 2 μm or more. If the radius of curvature R is too large, the area of ​​the opening 22 becomes small, and the detection accuracy of the sensor element decreases. From this perspective, the radius of curvature R is preferably 1 / 4 or less of the width of the opening 22 in the Y direction.

[0054] (Modifications 2 to 5 of the first embodiment) Fig. 6(a) is a plan view of a sensor element according to Modification 2 of the first embodiment of the present invention. Like the sensor element 102 according to Modification 2 of the first embodiment shown in Fig. 6(a), a plurality of openings 22 may be provided that overlap with the channel layer 14. The plurality of openings 22 may be arranged in either the Y direction or the X direction.

[0055] Fig. 6(b) is a plan view of a sensor element according to Modification 3 of the first embodiment of the present invention. As in sensor element 103 according to Modification 3 of the first embodiment shown in Fig. 6(b), the planar shape of opening 22 may be circular. Alternatively, the planar shape of opening 22 may be elliptical.

[0056] Fig. 7(a) is a plan view of a sensor element according to Modification 4 of the first embodiment of the present invention. As in sensor element 104 according to Modification 4 of the first embodiment shown in Fig. 7(a), the planar shape of opening 22 may be a hexagon with the corners of a rectangle cut off by straight lines.

[0057] Fig. 7(b) is a plan view of a sensor element according to Modification 5 of the first embodiment of the present invention. As in sensor element 105 according to Modification 5 of the first embodiment shown in Fig. 7(b), the planar shape of opening 22 may be an octagon with the corners of a rectangle cut off by straight lines.

[0058] As in modification 102 of the first embodiment, a plurality of openings 22 may be provided in one channel layer 14. From the viewpoint of suppressing adhesion of an object 56 to a corner 55 of the opening 22 or cracks 57 in the insulating layer 20 at the corners of the opening 22 as shown in FIG. 5(a), the rectangular corners 55 of the opening 22 may be curved or cut as shown in FIGS. 5(b) and 7(b). The planar shape of the opening 22 can be set arbitrarily in addition to the first embodiment and its modifications.

[0059] (Sixth Modification of the First Embodiment) FIG. 8(a) is a plan view of a sensor element according to Modification 6 of the first embodiment of the present invention, and FIG. 8(b) is a cross-sectional view taken along line AA of FIG. 8(a). As shown in FIGS. 8(a) and 8(b), the sensor element 106 according to Modification 6 of the first embodiment includes an insulating layer 26. The insulating layer 26 covers the end E1 of the channel layer 14. The insulating layer 20 covers at least a portion of the insulating layer 26. The insulating layer 26 has an opening 27 that exposes the channel layer 14. The width Y2 of the opening 27 in the Y direction is smaller than the width Y3 of the opening 22. The other configurations are the same as those of the first embodiment, and will not be repeated.

[0060] As in Modification 6 of the first embodiment, the insulating layer covering the end E1 of the channel layer 14 may be a stacked film of multiple insulating layers 20 and 26. This improves the coverage of the channel layer 14 by the insulating layers 20 and 26. Although an example has been described in which the width Y2 of the opening 27 is smaller than the width Y3 of the opening 22, the width Y2 may be the same as or larger than the width Y3. The number of insulating layers may be three or more.

[0061] (Seventh modification of the first embodiment) FIG. 9 is a cross-sectional view of a sensor element according to the seventh modification of the first embodiment of the present invention. As shown in FIG. 9, a pool 36 is not provided in a sensor element 107 according to the seventh modification of the first embodiment. The sample 31 is a gas containing a target substance 32 and other substances 34. A gate electrode 38a is provided in place of the substrate 10. The gate electrode 38a controls the Fermi level of the channel layer 14 via the insulating layer 12. The gate electrode 38a is, for example, a highly doped N-type or P-type silicon substrate. The gate electrode 38a may also be a metal substrate. The other configurations are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0062] In the configurations of Modifications 1 to 6 of the first embodiment, the sample 31 may be a gas. In this case, it is difficult to supply a potential from the gate electrode 38 to the channel layer 14 via the sample 31, as in the first embodiment. Therefore, by providing a gate electrode 38a below the channel layer 14, a potential can be supplied to the channel layer 14.

[0063] The target substance 32 may be a substance in a solution, as in the first embodiment and its modifications 1 to 6. The target substance 32 may be a substance in a gas, as in the seventh modification of the first embodiment.

[0064] (Eighth Modification of the First Embodiment) The eighth modification of the first embodiment is a sensor array in which the sensor elements of the first embodiment and its modifications are arranged in an array on the upper surface of the substrate 10. At least two of the plurality of sensor elements may have different planar shapes of the openings 22 (exposed areas). For example, the planar shapes of the openings 22 may be different depending on the type of target substance 32.

[0065] 10 is a block diagram of a sensor system that uses the first embodiment of the present invention and its modified examples. As shown in FIG. 10, the sensor system 100B includes a sensor element 64, a detection circuit 65, and a computer 66.

[0066] The sensor element 64 is a sensor element or sensor array according to the first embodiment, the second embodiment, and their modifications, and converts a physical quantity 67, such as the concentration of the target substance 32, into an electrical indicator 68, such as a voltage value, a current value, a resistance value, or a capacitance value. The detection circuit 65 converts the indicator 68 output by the sensor element 64 into a signal 69, such as a digital signal or an analog signal. The sensor element 64 and the detection circuit 65 form a sensor block 63. The computer 66 acquires the signal 69 output by the detection circuit 65 and performs data processing.

[0067] (Second embodiment) FIG. 11(a) is a plan view showing a sensor element according to a second embodiment of the present invention, and FIG. 11(b) is a cross-sectional view taken along the line AA of FIG. 11(a).

[0068] As shown in FIGS. 11(a) and 11(b), in the sensor element 110 according to the second embodiment, the insulating layer 20 has a plurality of openings 22 that expose the upper surface of the channel layer 14 so as to cover the electrodes 16, 18 and the channel layer 14. The plurality of openings 22 are provided in a region 15 on the channel layer 14 between the electrodes 16 and 18. The planar shape of the openings 22 is, for example, rectangular. The planar shape of the openings 22 can be appropriately set to a polygonal or circular shape, for example. The size and shape of the plurality of openings 22 may be the same as each other. At least two of the plurality of openings 22 may have different sizes or shapes.

[0069] Fig. 12 is a cross-sectional view of a sensor element according to a second embodiment of the present invention. Fig. 12 shows a state in which a sensor element 110A according to the first embodiment is in use. As shown in Fig. 12, in the sensor element 110A, the capture body 25 is bonded to the surface of the channel layer 14 exposed from the multiple openings 22. The other configurations are the same as those of the first embodiment, and therefore description thereof will be omitted.

[0070] In the sensor element 130 of the first comparative example shown in Figures 3(a) and 3(b), when the capture body 25 is bonded to the channel layer 14, a solution containing the capture body 25 is dropped onto the channel layer 14 and left to stand for a certain period of time. This causes an interaction between the atomic layer material in the channel layer 14 and the capture body 25, and the capture body 25 is bonded to the channel layer 14. However, the solution containing the capture body 25 may be dropped unevenly onto the channel layer 14 exposed from the opening 22.

[0071] In such a case, the number of capture bodies 25 bonded to the channel layer 14 increases in locations where a large amount of capture bodies 25 is supplied, and the number of capture bodies 25 bonded to the channel layer 14 decreases in locations where a small amount of capture bodies 25 is supplied. Therefore, the density of capture bodies 25 bonded to the channel layer 14 varies depending on the location in the planar direction. It is difficult to control the density of capture bodies 25 in the planar direction. This results in different sensitivities between the sensor elements 130. Furthermore, even if an attempt is made to provide a density distribution of capture bodies 25 in the planar direction of the channel layer 14, it is difficult to obtain the desired density distribution of capture bodies 25.

[0072] (Description of the second embodiment) In the sensor element 110 of the second embodiment, the channel layer 14 has a plurality of exposed regions corresponding to the openings 22 that are not covered by the insulating layer 20. The capture bodies 25 are hardly bonded to the insulating layer 20, but are bonded to the atomic layer material in the exposed regions of the channel layer 14 exposed through the openings 22. Therefore, even in places where a large number of capture bodies 25 are supplied, the number of capture bodies 25 bonded to the channel layer 14 is limited by the density (or aperture ratio) of the openings 22. This makes it possible to prevent the number of capture bodies 25 bonded to the channel layer 14 from increasing too much.

[0073] Even in areas where there is a small supply of capture bodies 25, if a sufficient number of capture bodies 25 are supplied to bond to the channel layer 14 exposed from the openings 22, the number of capture bodies 25 will be approximately the same as in areas where there is a large supply of capture bodies 25. In this way, the density of the capture bodies 25 in the planar direction can be controlled by the density of the openings 22. Therefore, the sensitivity between the sensor elements 130 can be made uniform. In addition, the density distribution of the capture bodies 25 in the planar direction of the channel layer 14 can be controlled to a desired density distribution.

[0074] The trapping body 25 is made of a material that bonds to the channel layer 14 but does not bond easily to the insulating layer 20. Even if the trapping body 25 is bonded to the insulating layer 20, the insulating layer 20 prevents the trapping body 25 from affecting the potential (Fermi level) of the channel layer 14 very much.

[0075] If there is an opening 22 among the plurality of openings 22 to which the capture body 25 is not bonded to the channel layer 14 within the opening 22, the target substance 32 or another substance 34 may be directly bonded to the channel layer 14. In this case, the potential (Fermi level) of the channel layer 14 changes unintentionally, causing changes in the characteristics of the sensor element. Therefore, it is preferable that the capture body 25 is bonded to the channel layer 14 within the opening 22 in all of the plurality of openings 22.

[0076] 13(a) and 13(b) are cross-sectional views of a sensor element according to a second embodiment of the present invention. As shown in FIG. 13(a), in sensor element 110B, target substance 32 is larger than that shown in FIG. 12. For example, if target substance 32 is a cell, microorganism, or pollen, the size of target substance 32 is approximately several tens of μm. In this case, if the spacing L1 of opening 22 is several μm, target substance 32c cannot penetrate between target substances 32a and 32b captured by capture bodies 25a and 25b. Therefore, capture body 25c cannot capture target substance 32c.

[0077] 13(b), in sensor element 110C, the spacing L2 of openings 22 is larger than the size of target substances 32. This reduces the number of capture bodies 25 that cannot capture target substances 32. Therefore, the number of target substances 32 that can be captured can be greater than in sensor element 110B.

[0078] Furthermore, if the target substances 32 have an electric charge, the target substances 32 are subjected to a repulsive force due to the electrostatic force of the electric charge. Therefore, even if the capture bodies 25 are densely arranged, some capture bodies 25 will not be able to capture the target substances 32.

[0079] The higher the density of the openings 22, the higher the sensitivity of the sensor element, but as mentioned above, if some capture bodies 25 are produced that are unable to capture the target substance 32, the error will increase. Therefore, it is preferable to increase the spacing between the openings 22 to such an extent that no capture bodies 25 are produced that are unable to capture the target substance 32. The width and spacing of the openings 22 are, for example, 10 nm to 100 μm.

[0080] 11(a), an imaginary line 39 is provided that connects the electrode 16 and the electrode 18 and extends in the X direction. In this case, if the imaginary line 39 does not pass through the opening 22, the carriers that pass through the imaginary line 39 do not contribute to sensing. This increases the noise level of the sensor element 110, resulting in a decrease in sensitivity.

[0081] Therefore, every imaginary straight line 39 passing through the channel layer 14 passes through at least one opening 22. In other words, when viewed from the X direction, at least one of the openings 22 (exposed area) is provided in every region 15 of the channel layer 14. This reduces carriers that do not contribute to sensing. This reduces the noise level of the sensor element 100 and improves sensitivity.

[0082] (Modification 1 of the second embodiment) FIG. 14(a) is a cross-sectional view of a sensor element according to Modification 1 of the second embodiment of the present invention. As shown in FIG. 14(a), a sensor element 111 according to Modification 1 of the second embodiment of the present invention includes a gate electrode 38a. The gate electrode 38a is provided on a substrate 10 with an insulating layer 12 sandwiched therebetween. An insulating layer 20 is provided to cover the gate electrode 38a. The insulating layer 20 has an opening 23 on the upper surface of the gate electrode 38a. The opening 23 is provided in the pool 36, and the gate electrode 38a contacts the sample 30. The gate electrode 38a is formed, for example, simultaneously with the electrodes 16 and 18. In the sensor element 111, the distance between the gate electrode 38a and the channel layer 14 can be set with high precision. Furthermore, miniaturization is possible. The other configurations are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0083] (Modification 2 of the second embodiment) Fig. 14(b) is a cross-sectional view of a sensor element according to Modification 2 of the second embodiment of the present invention. As shown in Fig. 14(b), a sensor element 112 according to Modification 2 of the second embodiment includes a gate electrode 38b and a gate insulating film 24. The gate electrode 38b is provided on the substrate 10 with an insulating layer 12 sandwiched therebetween. The gate insulating film 24 is provided between the gate electrode 38b and the channel layer 14. The other configurations are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0084] The sensor element 112 is a dual-gate transistor having two gate electrodes, gate electrodes 38 and 38b. For example, the gate electrode 38 sets the potential (Fermi level) of the channel layer 14, and the gate electrode 38b can finely adjust the potential (Fermi level) of the channel layer 14. For example, when the sensor elements 112 are arrayed, the gate electrode 38b can be used to finely adjust the potential of the channel layer 14 for each sensor element 112. The potential of the channel layer 14 may be controlled using the gate electrode 38b without providing the gate electrode 38.

[0085] The gate electrodes 38a and 38b may be made of the same material as the above-described electrodes 16 and 18. The thickness of the material of the gate electrodes 38a and 38b is preferably 100 nm or more to reduce resistance, and is preferably 1 μm or less to improve coverage of the gate insulating film 24 on the gate electrode 38b.

[0086] The gate insulating film 24 is an aluminum oxide film, silicon oxide film, hafnium oxide film, tantalum oxide film, or titanium oxide film formed by ALD, a silicon nitride film or silicon oxide film formed by CVD, or silicon oxide formed by sputtering, or a laminate film thereof. To efficiently supply a potential to the channel layer 14, the thickness of the gate insulating film 24 is preferably 5 nm to 1 μm, and the relative dielectric constant of the gate insulating film 24 is preferably greater than that of, for example, silicon oxide.

[0087] (Modification 3 of the second embodiment) FIG. 15(a) is a cross-sectional view of a sensor element according to Modification 3 of the second embodiment of the present invention. As shown in FIG. 15(a), a sensor element 113 according to Modification 3 of the second embodiment does not have a pool 36. The sample 31 is a gas containing a target substance 32 and other substances 34. A gate electrode 38c is provided instead of the substrate 10. A channel layer 14 is provided on the gate electrode 38c with a gate insulating film 24 sandwiched therebetween. The gate electrode 38c controls the potential of the channel layer 14 via the gate insulating film 24. The gate electrode 38c is, for example, a highly doped N-type or P-type silicon substrate. The gate electrode 38c may also be a metal substrate. The other configurations are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0088] When the sample 31 is a gas, it is difficult to supply a potential from the gate electrode 38 to the channel layer 14 via the sample 31, as in the second embodiment. Therefore, by providing a gate electrode 38b or 38c below the channel layer 14, a potential can be supplied to the channel layer 14.

[0089] (Modification 4 of the second embodiment) Fig. 15(b) is a cross-sectional view of a sensor element according to Modification 4 of the second embodiment of the present invention. As shown in Fig. 15(b), a pool 36 is not provided in a sensor element 114 according to Modification 4 of the second embodiment. The sample 31 is a gas containing a target substance 32 and other substances 34. The other configurations are the same as those of Modification 2 of the second embodiment, and therefore a description thereof will be omitted.

[0090] The target substance 32 may be a substance in a solution, as in the second embodiment and its modifications 1 and 2. The target substance 32 may be a substance in a gas, as in modifications 3 and 4 of the second embodiment.

[0091] (Fifth Modification of the Second Embodiment) Fig. 16(a) is a cross-sectional view of a sensor element according to Modification 5 of the second embodiment of the present invention. As shown in Fig. 16(a), in a sensor element 115 according to Modification 5 of the second embodiment, a channel layer 14 is provided on part of the side and upper surfaces of the electrodes 16 and 18. The other configurations are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0092] In the sensor element 115, the channel layer 14 is formed after the electrodes 16 and 18 are formed. Therefore, compared to the sensor element 110 of the second embodiment, one process after the formation of the channel layer 14 can be reduced. If residues or the like remain on the channel layer 14 in the processes after the formation of the channel layer 14, the characteristics of the sensor element will deteriorate. For example, if the channel layer 14 is made of graphene, the characteristics of the sensor element are likely to deteriorate if photoresist used in each process remains as residue. In the sensor element 115, the process after the formation of the channel layer 14 can be reduced, thereby suppressing deterioration of the characteristics.

[0093] (Modification 6 of the second embodiment) Fig. 16(b) is a cross-sectional view of a sensor element according to Modification 6 of the second embodiment of the present invention. As shown in Fig. 16(b), in a sensor element 116 according to Modification 6 of the second embodiment, the electrodes 16 and 18 are embedded in the insulating layer 12. The upper surfaces of the insulating layer 12 and the electrodes 16 and 18 are flat. This makes it possible to suppress the application of stress to the channel layer 14. It also makes it easier to form a flow path on the sensor element 116. The other configurations are the same as those of the second embodiment, and therefore a description thereof will be omitted.

[0094] (Seventh modification of the second embodiment) 17(a) to 17(c) are plan views of sensor elements according to Modification 7 of the second embodiment of the present invention. As shown in Fig. 17(a) to 17(c), in sensor elements 117A to 117C according to Modification 7 of the second embodiment, the density of openings 22 differs between a central portion 40 and a peripheral portion 41 of a region 15 on a channel layer 14 between electrodes 16 and 18.

[0095] 17(a), in the sensor element 117A, the openings 22 are densely arranged in the central portion 40. In the peripheral portion 41, the density of the openings 22 decreases toward the outer periphery of the region 15. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0096] 17(b), in the sensor element 117B, the openings 22 are densely provided in the central portion 40. Almost no openings 22 are provided in the peripheral portion 41. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0097] 17(c), in the sensor element 117C, almost no openings 22 are provided in the central portion 40. The openings 22 are densely provided in the peripheral portion 41. In the central portion 40, the density of the openings 22 may decrease toward the center of the region 15. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0098] When sample 30 is introduced into sensor elements 117A to 117C, the sample 30 may first hit the central portion 40 and then flow to the peripheral portion 41. In this case, the flow of sample 30 may not be uniform in the peripheral portion 41. Therefore, as in sensor elements 117A and 117B, the density of openings 22 in the central portion 40 is increased to increase the density of capture bodies 25. The density of openings 22 in the peripheral portion 41 is decreased to decrease the density of capture bodies 25. This reduces the effect of non-uniform flow of sample 30 in the peripheral portion 41.

[0099] On the other hand, if the sample 30 is introduced into the central region 40 at high speed, the flow of the sample 30 in the central region 40 may not be uniform. After that, the flow of the sample 30 becomes uniform in the peripheral region 41. In such a case, as in sensor element 117C, the density of the openings 22 in the peripheral region 41 is increased to increase the density of the capture bodies 25. The density of the openings 22 in the central region 40 is decreased to decrease the density of the capture bodies 25. This reduces the effect of non-uniformity in the flow of the sample 30 in the central region 40.

[0100] As in the sensor elements 117A to 117C, the density of the openings 2 (exposed regions) 2 in the central portion 40 of the region 15 of the channel layer 14 may be made different from the density of the openings 22 (exposed regions) in the peripheral portion 41 of the region 15.

[0101] (Modification 8 of the second embodiment) 18(a) and 18(b) are plan views of a sensor element according to Modification 8 of the second embodiment of the present invention. As shown in Fig. 18(a) and Fig. 18(b), in sensor elements 118A and 118B according to Modification 8 of the second embodiment, the density of the openings 22 differs between a central portion 42 in the X direction of a region 15 and a peripheral portion 43 in the X direction.

[0102] 18(a), in the sensor element 118A, almost no openings 22 are provided in the central portion 42. The openings 22 are densely provided in the peripheral portion 43. The openings 22 may be provided in the central portion 42 at a lower density than in the peripheral portion 43. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0103] When the sample 30 is introduced into the central portion 42 of the region 15 from the Y direction, as indicated by the arrow 48, the flow of the sample 30 may not be uniform in the central portion 42. The flow of the sample 30 becomes uniform in the peripheral portion 43. The density of the openings 22 is increased in the peripheral portion 43 where the flow of the sample 30 is uniform, and the density of the openings 22 is decreased in the central portion 42 where the flow of the sample 30 is not uniform. This reduces the effect on sensing caused by the non-uniform flow of the sample 30 in the central portion 42.

[0104] When the sample 30 is introduced into the peripheral portion 43 of the region 15 from the Y direction as indicated by the arrow 49, the density of the openings 22 in the peripheral portion 43 is increased. This makes it possible to detect the effect of the flow of the sample 30.

[0105] 18(b), in the sensor element 118B, almost no openings 22 are provided in the peripheral portion 43. The openings 22 are densely provided in the central portion 42. The openings 22 may be provided in the peripheral portion 43 at a lower density than in the central portion 42. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0106] When the sample 30 is introduced into the peripheral portion 43 of the region 15 from the Y direction, as indicated by arrow 49, the density of the openings 22 in the central portion 42 where the flow of the sample 30 is uniform is increased, and the density of the openings 22 in the peripheral portion 43 where the flow of the sample 30 is uneven is decreased. This reduces the effect on sensing due to unevenness in the flow of the sample 30 in the peripheral portion 43. Furthermore, when the sample 30 is introduced into the central portion 42 of the region 15 from the Y direction, as indicated by arrow 48, the density of the openings 22 in the central portion 42 is increased. This makes it possible to detect the effect of the flow of the sample 30.

[0107] (Modification 9 of the second embodiment) 19(a) and 19(b) are plan views of a sensor element according to a ninth modification of the second embodiment of the present invention. As shown in FIG. 19(a), in a sensor element 119A according to the ninth modification of the second embodiment, the density of the openings 22 differs in a region 44a on the -X side of the region 44a, a region 44b on the +X side of the region 44a, and a region 44c on the +X side of the region 44a in the region 15. Specifically, the density of the openings 22 decreases from the regions 44a to 44c. The other configurations are the same as those of the second embodiment, and therefore description thereof will be omitted.

[0108] 19(b), in sensor element 119B, the density of openings 22 differs in region 45a on the -Y side of region 15, region 45b on the +Y side of region 45a, and region 45c on the +Y side of region 45a. Specifically, the density of openings 22 decreases from region 45a to 45c. The other configurations are the same as those in the second embodiment, and therefore description thereof will be omitted.

[0109] 19(a) and 19(b), when sample 30 is introduced from the direction of arrow 48, the flow rate of sample 30 is fast in regions 44a and 45a, making it difficult for target substance 32 to be captured by capture body 25. On the other hand, the flow rate of sample 30 is slow in regions 44c and 45c, making it easy for target substance 32 to be captured by capture body 25. Therefore, the density of openings 22 is reduced from regions 44a to 44c and from regions 45a to 45c. This allows target substance 32 to be captured to the same extent in all regions 44a to 44c and all regions 45a to 45c.

[0110] Furthermore, when the sample 30 is introduced from the direction of the arrow 49, the sample 30 hits regions 44a and 45a, causing the flow of the sample 30 to become uneven. Therefore, the density of the openings 22 is increased from region 44c to 44a and from 45c to 45a. This reduces the effect on sensing of the uneven flow of the sample 30.

[0111] As in sensor elements 118A to 119B, a density distribution of a plurality of openings 22 (exposed areas) is provided in the introduction direction of sample 30 or in a direction perpendicular to the introduction direction. This allows capture bodies 25 to be provided taking into account the flow of sample 30. In the ninth modification of the second embodiment, an example in which region 15 is divided into three regions has been described, but region 15 may also be divided into two or four or more regions.

[0112] (Modification 10 of the second embodiment) 20(a) to 20(c) are plan views of sensor elements according to a tenth modification of the second embodiment of the present invention. In sensor element 120A of FIG. 20(a), the density of openings 22 in region 15 is high. In sensor element 120B of FIG. 20(b), the density of openings 22 in region 15 is medium. In sensor element 120C of FIG. 20(c), the density of openings 22 in region 15 is low.

[0113] In sensor element 120A, the density of openings 22 is high, and therefore the density of capture bodies 25 is also high. In sensor element 120A, even if the concentration of target substance 32 in sample 30 is high, there are capture bodies 25 that do not capture target substance 32. Therefore, the amount of change in the characteristics of sensor element 120A (such as the current between electrodes 16 and 18 or the voltage at the Dirac point) does not saturate.

[0114] On the other hand, in sensor element 120C, the density of capture bodies 25 is low. Therefore, even if the concentration of target substance 32 in sample 30 is low, most of capture bodies 25 capture target substance 32. As a result, the amount of variation in the characteristics of sensor element 120C becomes saturated.

[0115] Therefore, three types of sensor elements, 120A to 120C, are prepared, and the sample 30 is introduced into the sensor elements 120A to 120C. If the characteristics of all of the sensor elements 120A to 120C are not saturated, the concentration of the target substance 32 in the sample 30 is low. If the characteristics of the sensor element 120C are saturated and the characteristics of the sensor elements 120A and 120B are not saturated, the concentration of the target substance 32 in the sample 30 will be the second lowest.

[0116] If the characteristics of sensor elements 120B and 120C are saturated but the characteristics of sensor element 120A are not saturated, the concentration of target substance 32 in sample 30 is the second highest. If the characteristics of sensor elements 120A to 120C are all saturated, the concentration of target substance 32 in sample 30 is the highest. In this way, the concentration of target substance 32 in sample 30 can be determined simply. In modification 10 of the second embodiment, three types of sensor elements 120A to 120C with different densities of openings 22 are prepared, but the number of types of sensor elements with different densities of openings 22 may be two or four or more.

[0117] (Modification 11 of the second embodiment) FIG. 21 is a plan view of a sensor array according to Modification 11 of the second embodiment of the present invention. The sensor array 121 of FIG. 21 includes a plurality of each of sensor elements 120A to 120C. By averaging the detection results of the sensor elements 120A to 120C, the effects of fluctuations in the sample 30, non-uniform flow, non-uniform flow speed, etc. can be suppressed. This improves detection accuracy. The sensor elements 120a to 120C may be arranged regularly or randomly. The rest of the configuration is the same as Modification 10 of the second embodiment, and therefore a description thereof will be omitted.

[0118] (Modification 12 of the second embodiment) Fig. 22 is a plan view of a sensor array according to a twelfth modification of the second embodiment of the present invention. The sensor array 122 of Fig. 22 includes a plurality of partitions 60. A plurality of flow paths 62A to 62C are provided between the partitions 60. A plurality of sensor elements 120A, a plurality of sensor elements 120B, and a plurality of sensor elements 120C are provided in the flow paths 62A to 62C, respectively. A sample 30 is introduced into the flow paths 62A to 62C as indicated by arrows 48. The other configurations are the same as those of the eleventh modification of the second embodiment, and therefore a description thereof will be omitted.

[0119] When sensor elements 120A to 120C are mounted on the same substrate 10, interference may occur between different types of sensor elements 120A to 120C. Therefore, sensor elements of the same type (e.g., sensor element 120A) among sensor elements 120A to 120C are provided in the same flow path (e.g., flow path 62A) as in sensor array 122. This makes it possible to suppress interference between different sensor elements 120A to 120C, and by averaging the detection results of sensor elements of the same type (e.g., sensor element 120A), it is possible to improve detection accuracy.

[0120] In the examples of Modifications 11 and 12 of the second embodiment, examples have been described in which a plurality of each of the three types of sensor elements 120A to 120C is provided, but the number of types of sensor elements may be one, two, or four or more. By varying the density of the openings 22 (exposed areas) in at least two of the plurality of sensor elements, various information can be detected. The arrayed sensor elements may be those of the first embodiment and its modifications, and Modifications 1 to 9 of the second embodiment.

[0121] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0122] The above-disclosed embodiments include, for example, the following aspects. (1) A first electrode; A second electrode; a channel layer including an atomic layered material, the channel layer being disposed between the first electrode and the second electrode and electrically connected to the first electrode and the second electrode; an insulating layer covering at least an end of the channel layer in a direction perpendicular to the arrangement direction of the first electrode and the electrodes; A sensor element comprising: (2) The sensor element according to (2), wherein the channel layer has an exposed region that is not covered by the insulating layer. (3) The sensor element according to (2), wherein, in a top view, the channel layer in the exposed region includes a capture body that binds to the atomic layer material and captures a target substance. (4) The sensor element according to (2) or (3), wherein at least a part of the contour of the exposed area is curved. (5) The sensor element according to any one of (1) to (4), wherein the insulating layer covering the end of the channel layer is a laminated film. (6) The sensor element according to any one of (1) to (5), wherein the atomic layer material includes graphene. (7) The sensor element according to (2), wherein the insulating layer has a plurality of the exposed regions. (8) The sensor element according to any one of (1) to (7), wherein the sensor element detects a target substance in a solution. (9) The sensor element according to any one of (1) to (7), wherein the sensor element detects a target substance in a gas. (10) A sensor array having a plurality of sensor elements of any one of (1) to (9). (11) (2) or (3) is provided with a plurality of sensor elements. A sensor array, wherein the exposed regions of at least two of the plurality of sensor elements have different shapes. [Explanation of symbols]

[0123] 10: Circuit board 12, 20, 26: Insulating layers 14: Channel layer 16, 18: Electrode 22, 27; aperture 25, 25a, 25b, 25c: Captured body 30, 31: Sample 32, 32a, 32b, 32c Target substance 40, 42: Central part 41, 43: Periphery [Prior art documents] [Patent documents]

[0124] [Patent Document 1] Japanese Patent Publication No. 2021-043169

Claims

1. A first electrode; A second electrode; a channel layer including an atomic layered material, the channel layer being disposed between the first electrode and the second electrode and electrically connected to the first electrode and the second electrode; an insulating layer covering at least an end of the channel layer in a direction perpendicular to the arrangement direction of the first electrode and the electrodes; A sensor element comprising:

2. The sensor element according to claim 1 , wherein the channel layer has an exposed region that is not covered by the insulating layer.

3. The sensor element according to claim 2 , wherein, in a top view, the channel layer in the exposed region includes a capture body that binds to the atomic layer material and captures a target substance.

4. 4. The sensor element according to claim 2, wherein at least a part of the contour of the exposed area is curved.

5. The sensor element according to claim 1 , wherein the insulating layer covering the end of the channel layer is a laminated film.

6. The sensor element according to claim 1 , wherein the atomic layer material includes graphene.

7. The sensor element according to claim 2 , wherein the channel layer has a plurality of the exposed regions.

8. The sensor element according to claim 1 , wherein the sensor element detects a target substance in a solution.

9. The sensor element according to claim 1 , wherein the sensor element detects a target substance in a gas.

10. A sensor array comprising a plurality of sensor elements according to any one of claims 1 to 3.

11. A sensor device comprising a plurality of the sensor elements according to claim 2 or 3. A sensor array, wherein the exposed regions of at least two of the plurality of sensor elements have different shapes.

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